Water valve for rock drills

ABSTRACT

A water valve for an air operated rock drill for controlling the flow of water from a water supply passage to the water feed tube of the drill. The valve is designed to prevent the water pressure from exceeding the air pressure. The valve includes a piston which is acted on by air under pressure to be opened to permit the flow of water from the supply passage to the feed tube. A passage in the valve piston permits the flow of water from the water feed tube to the side of the valve piston opposite from the side which is acted on by the air pressure. If the water pressure exceeds the air pressure, the piston will be moved toward a closed position to prevent the flow of additional water from the supply into the water tube until such time as the water pressure is reduced to a point below that of the air pressure.

[4 1 Apr. 1, 1972 oychuk et a1.

3,513,878 5/1970 Smith................... ...l37/509X [54] WATER VALVE FOR ROCK 1'1 L115 3 M 3 7 SW NW mw m A" mm .Lm m P. Am Rm wm ma Er G Mn- N& Gm H/ R6 0 F4 6 4 4 7 6 [72] Inventors: Ronald R. Boychuk; Sigmund 1. SM- temoen, both of Sudbury, Ontario, Canada Primary Examiner-Samuel B. Rothberg Assistant Examiner--David J. Zobkiw [22] Filed:

Attorney-Frank S. Troidl and David W. Tibbott ABSTRACT [21] App1.No.:

piston opby the air pressure. If pressure, the piston will be to prevent the flow of additional water from the supply into the water tube until such time as the water pressure is reduced to a the air pressure.

A water valve for an air operated rock drill for controlling the flow of water from a water supply passage to the water feed 137505.13 tube of the drill. The valve is designed to prevent the water 1375051 509 pressure from exceeding the air pressure. The valve includes a piston which is acted on by air under pressure to be opened to permit the flow of water from the supply passage to the feed tube. A passage in the valve piston permits the flow of water from the water feed tube to the side of the valve posite from the side which is acted on the water pressure exceeds the air moved toward a closed position -137/509 X point below that of 137/505.28 37/505.13 X ....137/505.l3

Int Cl References Cited UNITED STATES PATENTS 887,801 5/1908 Hellrnan et al.......

2,727,530 12/1955 Grove etal 4/1941 Ernst..........

509,880 5/1950 Pe1ton.......

721,576 10/1955 Grove et a1 [58] Field ofSearch...................

Lebourg....

6 Claims, 2 Drawing Figures Lundeen...

WATER VALVE FOR ROCK DRILLS BACKGROUND OF THE INVENTION In the rock drilling art, it is known to supply water to a water feed tube of a rock drill to permit water to be conducted down the hole being drilled. Such water serves to wet down the cuttings and flush them out of the hole being drilled to thereby reduce dust. Ideally, the water pressure in the water feed tube should be less than the air pressure used to operate the drill. If the water pressure in the feed tube exceeds the air pressure, the water will tend to back up into the air passages and thereby effect operation of the drill, eventually causing corrosion of the vital parts of the drill.

Because line water pressure often varies, it is not always possible to insure that line water pressure is less than line air pressure. Water valves in use prior to the present invention do not always maintain the water pressure in the water tube less than the air pressure. In present water valves, the water pressure in the water feed tube is dependent upon the line water pressure. Thus, the water pressure in the feed tube can exceed air pressure and water can back up into air passages. Some water valves now in sue are designed to maintain a certain water pressure in the feed tube, but they do not insure that this pressure is less than the air pressure. In addition, these valves have proved to be unduly complex in construction. It would be desirable to provide a water valve for a rock drilling device wherein the water pressure in the water feed tube was maintained as a function of the air pressure used to operate the drill.

SUMMARY It is the principle object of this invention to provide a water valve for a rock drilling machine which controls the pressure of the water in the water feed tube as a function of line air pressure.

It is another object of this invention to provide a simply constructed water valve for a rock drilling device which maintains the water pressure in the feed tube less than line air pressure.

It is a further object of this invention to provide a rock drill including a water valve which insures that the water pressure in the feed tube is less than the air pressure used to operate the drilling device.

In general, the foregoing and other objects will be carried out by providing a water valve for an air operated rock drill for controlling the flow of water from a water supply passage to the water feed tube of the rock drill comprising: a casing defining a cylinder; a piston mounted for reciprocal movement in said cylinder between a closed position which prevents the flow of water from the water supply passage to the feed tube and an open position which permits the flow of water from the supply passage to said feed tube; passage means for conducting air under pressure to said cylinder on one side of said piston for moving said piston toward said open position; and passage means for selectively conducting water from the feed tube to the other side of said piston.

BRIEF DESCRIPTION OF THE DRAWING The invention will be described in connection with the annexed drawing wherein:

FIG. 1 is a sectional view of the backhead of a drilling machine; and

FIG. 2 is a fragmentary sectional view on an enlarged scale of the water valve of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The water valve of the present invention is designed to control the flow of water from a supply to the water feed tube of a rock drilling machine. A drilling machine such as a stoper is partially shown in FIG. 1 and generally indicated at 1. The drill includes a casing 2 and a backhead 3. An operating handle 4 including operating valves is connected to the backhead. The casing 2 defines a cylinder 5 with a piston 6 sliding therein. The piston 6 is adapted to reciprocate within the cylinder 5 and deliver an impact to a workpiece in a conventional manner. As is conventional in drilling machines of the type used for underground work, the drill is provided with a water feed tube 7. A water valve generally indicated at 8 is mounted in the backhead 3 of the drilling machine 1 for controlling the flow of water to the feed tube 7.

The water valve 8 of the present invention includes a valve body 10 threadedly secured in the backhead 3. The valve body 8 is provided with an axial bore 12 therethrough which is counterbored at 14, 16 and 18 as shown in FIG. 2. A valve piston 20 is mounted for reciprocal movement in the bore 12 and is provided with a stern portion 22. Suitable O-ring seals 24 and 25 are provided on the piston 20.

The water tube 7 having a flange 9 on one end extends into the counterbore 18 of the valve body 10. The tube 7 is secured in the valve body 10 by means of washers 30 and 32 and suitable O-ring seals 33 and 34. The washer 30 is provided with a valve seat 36 on one end thereof.

The bore 14 in the valve body 10 is closed by a cap 40 threadedly secured to the valve body and is provided with an o-ring seal 41. A spring 45 positioned between the cap 40 and the piston 20 biases the piston 20 towards a seated position against the seat 32. The piston 20 is provided with a bore 50 therethrough.

Air from a suitable source such as a compressor (not shown) is supplied through a passage 52 in the backhead 3 to an annulus in the backhead 3 and a passage 54 in the valve body 10. The passage 54 communicates with the counterbore 14 in the valve body and the air under pressure tends to move the piston 20 against the biasing force of the spring 45 to open the water valve. The passage 52 is also connected to the control handle 4 so that when the rock drill is turned on, air is conducted through passage 54 to automatically open the water valve.

The backhead 3 is also provided with a passage 60 providing communication between a source of water (not shown) and an annulus 62 in the backhead 3. The water flows from annulus 62 through a passage 63 between the valve body 10 and the backhead 3 and passages 64 and 65 between washer 30 and counterbores l8 and 16, respectively, and into a chamber 66 in the counterbore 16.

When the drill is turned on and air is conducted to the front face of piston 20, the piston 20 is moved up against the biasing force of spring 45 and the stem 22 lifts off valve seat 36 to open the water valve and permit water to flow into the feed tube 7. 1

The axial passage 50 in the piston 20 provides communica tion between the feed tube 7 and the rear face of the piston 20 and the bore 14. The water on the rear face of piston 20 and the spring 45 urge the piston toward the seat 36 against the force of the air tending to open the valve. In the event water pressure in the water feed tube 7 exceeds the air pressure on the front face of the piston 20 or reaches a pressure which when combined with the force of spring 45 exceeds the air pressure, the valve piston 20 will be moved to a seated or closed position to prevent additional water from being supplied to the water feed tube 7. When the pressure in the feed tube drops back to a pressure below the air pressure on the front face of piston 20, the valve will again be opened to permit the flow of water from the supply passage 52 to the feed tube 7.

From the foregoing it should be apparent that a simple water valve has been provided which insures that the water pressure is always marginally below air pressure regardless of the line water pressure. With this valve the water pressure is below the air pressure and water cannot get into the working part of the drill by backing up through the air passage to the vital parts of the drill.

We claim 1. A rock drill comprising:

a rock drill body including a water feed tube and a water supply passage for conveying water to said feed tube;

valve means interposed between said supply passage and said feed tube for controlling the flow of water into said feed tube;

said body including an air supply passage for conducting air under a predetermined pressure to said valve means for opening said valve means to permit the flow ofwater from said water supply passage to said feed tube; and;

means operatively associated with said valve means for preventing the water pressure in said feed tube from exceeding said predetermined pressure; said valve means being free to open without opposition from the pressure in said water supply passage.

2. The rock drill of claim 1 wherein said valve means includes a valve seat and a piston; said air supply passage being adapted to conduct air under pressure to one side of said piston for opening said valve means.

3. The rock drill of claim 2 wherein said means for preventing said water pressure from exceeding said predetermined pressure includes passage means for conducting water from said feed tube to the other side of said piston so that said valve means will move to a closed position if the water pressure in said feed tube exceeds said predetermined pressure.

4. The rock drill ofclaim 2 further comprising spring means positioned on the other side of said piston for urging said valve means into a closed position and said means for preventing said water pressure from exceeding said predetermined pressure includes passage means for conducting water from said feed tube to the other side of said piston so that said valve means will move to a closed position before the water pressure in said feed tube exceeds said predetermined pressure.

5. The rock drill of claim 4 wherein said piston is provided with an axial passage therethrough to define said passage means for conducting water from said feed tube to the other side of said piston.

6. A water valve for an air-operated rock drill for controlling the flow of water from a water supply passage to a water feed tube ofthe rock drill comprising:

a valve member and a valve seat adapted to be engaged to close off the water flowing from the water supply passage to the water feed tube;

a body defining a cylinder;

a piston connected to said valve member for reciprocal movement in unison and mounted in said cylinder for movement toward said valve seat to a position wherein the valve is closed to prevent the flow of water from the water supply passage to the feed tube and away from said valve seat to a position wherein the valve is open to permit the flow of water from the supply passage to the feed tube;

first passage means for conducting air under pressure to said cylinder on one side of said piston for moving the valve member toward its open position;

second passage means for conducting water from the feed tube to the other side of said piston to urge said valve member toward its closed position, said second passage means being sealed off from said water supply passage when said valve member is in its closed position, wherein the water pressure in said water supply passage cannot prevent said valve member from opening; and

spring means located in said body wherein it urges said piston toward the closed position ofthe valve member. 

1. A rock drill comprising: a rock drill body including a water feed tube and a water supply passage for conveying water to said feed tube; valve means interposed between said supply passage and said feed tube for controlling the flow of water into said feed tube; said body including an air supply passage for conducting air under a predetermined pressure to said valve means for opening said valve means to permit the flow of water from said water supply passage to said feed tube; and; means operatively associated with said valve means for preventing the water pressure in said feed tube from exceeding said predetermined pressure; said valve means being free to open without opposition from the pressure in said water supply passage.
 2. The rock drill of claim 1 wherein said valve means includes a valve seat and a piston; said air supply passage being adapted to conduct air under pressure to one side of said piston for opening said valve means.
 3. The rock drill of claim 2 wherein said means for preventing said water pressure from exceeding said predetermined pressure includes passage means for conducting water from said feed tube to the other side of said piston so that said valve means will move to a closed position if the water pressure in said feed tube exceeds said predetermined pressure.
 4. The rock drill of claim 2 further comprising spring means positioned on the other side of said piston for urging said valve means into a closed position and said means for preventing said water pressure from exceeding said predetermined pressure includes passage means for conducting water from said feed tube to the other side of said piston so that said valve means will move to a closed position before the water pressure in said feed tube exceeds said predetermined pressure.
 5. The rock drill of claim 4 wherein said piston is provided with an axial passage therethrough to define said passage means for conducting water from said feed tube to the other side of said piston.
 6. A water valve for an air-operated rock drill for controlling the flow of water from a water supply passage to a water feed tube of the rock drill comprising: a valve member and a valve seat adapted to be engaged to close off the water flowing from the water supply passage to the water feed tube; a body defining a cylinder; a piston connected to said valve member for reciprocal movement in unison and mounted in said cylinder for movement toward said valve seat to a position wherein the valve is closed to prevent the flow of water from the water supply passage to the feed tube and away from said valve seat to a position wherein the valve is open to permit the Flow of water from the supply passage to the feed tube; first passage means for conducting air under pressure to said cylinder on one side of said piston for moving the valve member toward its open position; second passage means for conducting water from the feed tube to the other side of said piston to urge said valve member toward its closed position, said second passage means being sealed off from said water supply passage when said valve member is in its closed position, wherein the water pressure in said water supply passage cannot prevent said valve member from opening; and spring means located in said body wherein it urges said piston toward the closed position of the valve member. 